Two-stage push button switch

ABSTRACT

A two-stage, push button switch which has a single spring so mounted that it acts like a light spring during the first stage of the operation of the switch, but like a heavy spring during the second stage.

United States Patent Hayden July 22, 1975 [54] TWO-STAGE PUSH BUTTON SWITCH 3,162,735 12/1964 Williams 200/80 R 3,2 l 80 R [75] Inventor: Julian D. Hayden, Vancouver, 10 486 10/ 965 Holzer 200/ Wash. Primary Examiner-Robert K. Schaefer [73] Asslgnee. Syndyne Corporation, Vancouver, Assistant Examiner wimam J. Smith Wash.

Attorney, Agent, or Fzrm-Klarqmst, Sparkman, [22] Filed: Sept. 1, 1971 Campbell, Leigh, Hall & Whinston [21] Appl. No.: 176,870

[57] ABSTRACT [52] U.S. C1 200/159 R [51] Int. Cl. HOlh 13/52 A two-stage, push button switch which has a single [58] Field of S ar h ZOO/159 1 6- 30 spring so mounted that it acts like a light spring during ZOO/16 16 16 D the first stage of the operation of the switch, but like a heavy spring during the second stage. [56] References Cited UNITED STATES PATENTS 9/1960 Scheffer 200/159 R 8 Claiins, 13 Drawing Figures PATENTEDJUL 22 ms SHEET UP i 5T 2ND. DOWN LIMT' cuosuRE CLCSURE LlM-IT BUTTON TRAVEL PATENTEDJUL22 ms 895; 283

SHEET 2 TWO-STAGE PUSH BUTTON SWITCH The present invention relates to a two-stage, push button switch of the kind which offers a sharp rise in resistance after the first stage of operation of the switch, giving the operator the option of actuating the switch no further, or continuing the operation by overcoming the heavier resistance. Such a switch can be constructed with two springs, a light spring and a heavy spring.

A main object of the present invention is to provide a two-stage push button switch which requires only one spring, so mounted that the switch has a feel like that of the two-spring switch mentioned above.

Various other objects of the invention will be apparent from the following description taken in connection with the appended drawings, wherein:

FIG. 1 is a midsectional view through a push button switch incorporating the concepts of the present invention;

FIG. 2 is a section through the switch, taken along lines 22 of FIG. 1;

FIGS. 3-6 are diagrammatic views of the switch showing successive stages of its operation, FIGS. 3 and 4 being taken at right angles from the disposition of FIGS. 1 and 2, while FIGS. 5 and 6 have the same orientation as FIGS. 1 and 2',

FIG. 7 is a graph showing the resistance or force met in the travel of the push button of the switch;

FIG. 8 is a horizontal section through a modified form of switch, FIG. 8 being oriented like FIG. 2;

FIG. 9 is a diagrammatic view of a further modified form of switch, the figure being oriented like FIG. 3;

FIG. 10 is a diagrammatic view of still another modified form of my switch;

FIG. 11 is a vertical cross section through another form of my switch;

FIG. 12 is an inclined view taken along line 12-12 of FIG. 11;

FIG. 13 is a vertical section of still another form of my switch.

The particular switch shown in FIGS. 1 and 2 was designed for use in an electronic organ, and represents only one commercial adaptation of the invention. In an organ, the switch housing 12 is conventionally mounted in a panel from the front and is retained in place by a suitable adhesive, or a conventional securing means. In such position, its axis will be horizontal, rather than vertical as is shown in the drawings.

Referring to FIGS. 1 and 2, the two-stage push button switch there shown includes a push button or plunger 11, having a head 11a slidably fitting within upwardly extending annular flange 12a of the housing 12. The housing is generally cup-shaped and has a central bore in its lower wall 12b slidably receiving a stem 11b of the push button 11, so that the latter can slide axially in housing 12.

A contact ring 13 and a coil spring 14 surround the stem 11b of the button. The spring is compressed between the head lla of the button and the contact ring 13, and presses the latter against the upper leg 15a of a generally U-shaped stop clip 15.

The leg 15a fits through a bore in the stern 11b. The bore is offset from the axis of the stem 11b (FIG. 3) so that the spring 14 causes the ring contact to tilt to bring it against the head of the pin contact 16. The ring contact, in the open position of the switch, is spaced above the heads of a pair of other pin contacts 17 and The clip 15 has a midportion 15b riding in a slot 19 formed in the housing 12. The lower leg of the clip is bent to provide a detent 15d that fits in a notch 11d formed in the lower end of the stem 11b. The leg 15c abuts against a stop 20 formed on the housing 12 to limit upward movement of the button 11 relative to the housing 12. Downward travel of the button is limited by the engagement of the upper leg 15a with the bottom wall 21 of a channel 22 formed in the base 12b of the housing.

The cooperative engagement of the walls of the slot 19 and the midportion 15b of the clip prevent rotation of the push button relative to the housing during relative axial movement therebetween, while the biasing engagement of the ring contact 13 with the pin contact 16 urges the button upwardly to bring the lower leg 15c of the clip 15 against stop 20.

The shanks of the pin contacts 16, 17 and 18 are fixed in the bottom wall 121; of the housing 12, and project through such wall. The projecting portions serve as wiring terminals for the switch.

In an actual switch, such as shown in FIGS. 1 and 2, the heads of contacts 16, 17 and 18 are preferably disposed at different levels, and the contact ring is inclined from left to right as the parts are shown in FIG. 1 by the inclination of the upper leg 15a of the stop clip 15. This inclination, together with the different levels of the heads of the pin contacts minimizes the effect of tilting distortion on the spring as the push button is depressed in the second stage of its travel. It also permits the contact 18 to be situated at a level comparable to that of the other two contacts.

However, for purposes of simplicity, FIG. 5 (which is oriented the same as FIG. 1) shows the upper leg of the stop clip 15 in a horizontal position. Also FIG. 3 shows the heads of pins 16 and 17 at the same level. The principle of operation of the switch is substantially the same regardless of the inclination of the upper leg, and the levels of the heads of pins 16 and 17.

Referring to FIGS. 36, the line of action of the spring is indicated at 14. To make the explanation clearer, it has been assumed that the spring force is 2.5 pounds (FIG. 7 is based on this assumption). The force does not vary much as the spring is compressed.

When the switch is open, as shown in FIG. 3, the contact ring 13 is in engagement only with the head of pin contact 16. When the ring is brought into engagement with pin contacts 17 or 18, electrical circuits (not shown) are completed.

In FIG. 3, the total spring force is divided between the pin contact 16 and the stop clip 15. The offset of stop clip 15 from the axis of the push button is shown as being about one-fifth the distance from the stop clip to the contact 16. This means that the spring force will be divided between the pin contact 16 and the clip 15, with the pin contact 16 bearing a one-half pound load, while the clip 15 takes the remaining two pound load. This means that it takes one-half pound force to depress the button from the FIG. 3 to the FIG. 4 position. This movement is represented by the line A in FIG. 7.

However, when the ring contact 13 engages the pin contact 17 (which completes an electrical circuit), further downward movement of the push button requires compression of the spring from its FIG. 5 to its FIG. 6 position. Such movement is resisted by a larger portion of the spring force, because the plane of the pins 16 and 17 is close to the spring axis 14.

Assume that the button is stationary, and the pins 16 and 17 are being moved upwardly. The resistance to such movement is determined by the distance of spring line 14 from the free end of leg 150, relative to the distance of the pin plane from such free end. Since the latter distance is somewhat greater, it has a mechanical advantage, but less than the mechanical advantage in FIG. 3. With the proportions shown in the drawings, the FIG. 5-FIG. 6 resistance to movement will be about one and one-half to two pounds. FIG. 7 shows it as two pounds. Such resistance is represented in FIG. 7 by the line C, line B representing the rise in resistance to button travel after the ring contact engages the head of pin 17.

Once the push button reaches the FIG. 6 position, the push button could be further depressed, assuming that the leg 15 has not yet reached the bottom wall 21 of the channel 22, but now, there is no mechanical advantage. So the full force of the spring has to be overcome directly. This increase in resistance force is represented by the line D in FIG. 7, while the further movement is indicated by the line E.

It is pointed out that the movement of the button, indicated by line E in FIG. 7, is not utilized in the FIG. 1 and 2 form of the invention (but it could be by adding a fourth pin contact and associated circuit).

The ring 13 may be considered as a lever or beam in calculating the effective resistive force of the spring relative to the push button.

FIG. 1 shows that the spring 14 is initially under compression in the rest position of the push button. This prestressing of the spring gives the proper initial feel or touch, because the initial depressive force is great enough to make the operator conscious that he has touched and is operating the switch. Furthermore, when the ring 13 engages contact 17, the increased resistance tells the operator of such engagement, so that he does not overrun contact 17. However, the resistance during button travel between one contact and just before reaching the next, does not increase much. If it did the switch would feel spongy and make the operator uncertain as to what stage of operation the switch was in.

In the switch shown in FIGS. 1-7, the ring 13 makes line, rather than point, contact with stop clip 15, until the ring engages a contact which tilts the ring away from such contact. Line contact prevents the ring from unwanted tilting, which would otherwise occur about an axis through the contact 16 and a single point of the stop clip. Such tilting would spoil the action of the switch.

FIG. 8 shows a modified form of the invention which is generally similar to FIG. 2, except that a fourth contact 16 has been added, the other three contacts being given the same numbers as in FIG. 2. Also the clip 15 of FIG. 2 has been replaced by a bump or lug 25. Contact 16 is located at the same level as contact 16. These contacts, together with the bump 25, prevent unwanted tilting movement of the ring contact 13. Thus, when the button 11 is depressed, the ring contact 13 will remain in engagement with both contacts 16 and 16' until the ring engages contact 17, at which time the ring will thereafter be tilted toward contact 18. The movement of the push button after the ring engages contact 17 will break the circuit which includes contacts 16 and 16' while establishing a circuit through contacts 16' and 17.

The bump 25 is utilized as a stop (to engage the associated bottom wall of the housing) to limit downward movement of the push button. A similar stop (not shown) located below bump 25 but on the lower end of the push button is used to limit upward movement of the push button.

FIG. 9 shows another modified form of the invention which is like the FIG. 1 form but has a fourth contact 16" located above the ring contact 13. There is a stop clip 15 like the FIG. 1 form of the invention. When the push button 11 is depressed, the circuit which includes contacts 16 and 16" is broken. Another circuit is completed when the ring comes in engagement with contact 17, etc.

FIG. 10 is a still further modified form of the invention which is generally similar to FIGS. 1 and 2, except that there are five contacts, two being 16 and 18, the remaining three being identified by the reference numerals 37, 39 and 41. Contact 37 is mounted on a spring member 43.

In the rest position of the switch, a circuit is completed through contacts 37 and 39. This circuit is broken when the ring 13 is moved downwardly to engage contact 37. Subsequently other circuits are made and broken in an obvious manner.

The push button shown in FIGS. 1-7 has a stern which guides and aligns the switch parts. It is possible to turn the stem inside out, as shown in FIGS. 1 1 and 12. The contacts and push button have the same relative positions as in the switch of FIGS. 1 and 2, and the action is exactly the same, but the parts are aligned and guided by a cylindrical skirt 51 on the push button 49 rather than by a stem. The ring contact is no longer ring-shaped, but instead, is a disc 53.

The stop clip is replaced by a stop pin 55 which corresponds to the upper leg 15a in FIG. 1. This pin limits upward and downward movement of the push button 49.

FIG. 13 is similar to FIG. 11 but a bent spring strip 61 replaces the coil spring 14 of FIG. 11.

A variety of additional normally open or normally closed contacts can be incorporated in my switch, as will be obvious to those skilled in the art.

What is claimed is:

l. A multiple stage push button switch comprising:

a push button,

a single spring resisting depression of the push button,

and means mounting said spring so that only a fraction of its resistive force resists depression of said button during one stage of operation, while a larger fraction resists depression during a second stage, and a still larger fraction is resisting depression during a third stage.

2. A multiple stage push button switch as in claim 1, wherein said means includes a lever acted on by said spring,

and wherein multiple contacts effect a shift in the effective resistive force of the spring on the button, said multiple contacts being spaced different distances from said lever.

3. A multiple stage push button switch as in claim 1, wherein said means includes a lever acted on by said spring and wherein said means includes abutment means spaced about the axis of said button and located and the lever is a circular member supported in part by a first support element carried by the push button axis, and in part by second support element located a distance from the spring axis which is greater than the distance between the closest portion of said first support element and said axis.

5. A multiple stage push button switch as in claim 4, wherein the spring is a coil spring, said push button having a stem surrounded by the spring,

the circular member being a washer surrounding the stem,

a housing in which said push button is mounted,

said second support element being one of plural contacts, which contacts are disposed in fixed relation in said housing on the side of said washer opposite said spring,

another of said contacts being disposed adjacent the remote side of said stem from said second support and being located to be engaged by said washer as it is depressed to cause said washer to tilt toward still another contact,

said contacts being disposed in spaced relation about the axis of said button.

6. A multiple stage push button switch as in claim 5, wherein said stem projects through said housing, said first support element comprising a clip having a portion passing through said stem to support said washer and confine said spring, and having another portion passing through an opening in said housing and having a latching fit with the projecting portion of said stem, said clip having portions engaging said housing in abutting relationship in both directions of movement of said button to limit the movement of said button relative to said housing and retain said button, spring, washer and housing in assembled condition.

7. A multiple-stage push button switch as in claim 1, wherein said push button is mounted on a housing for movement relative thereto,

said means including a lever means establishing stepped operative connections between said spring and said housing to provide abrupt increases in resistance to push button movement as the latter is depressed.

8. A multiple stage plunger switch comprising:

plural spaced contacts,

a tilt contact member,

a plunger,

and means operatively connecting the plunger and the tilt contact member to cause the latter to tilt about a first axis to engage at least one contact and subsequently tilt about another axis, angularly related to the first axis, to engage at least one other contact,

said means including a single spring,

said spring applying a biasing pressure to said contact member. 

1. A multiple stage push button switch comprising: a push button, a single spring resisting depression of the push button, and means mounting said spring so that only a fraction of its resistive force resists depression of said button during one stage of operation, while a larger fraction resists depression during a second stage, and a still larger fraction is resisting depression during a third stage.
 2. A multiple stage push button switch as in claim 1, wherein said means includes a lever acted on by said spring, and wherein multiple contacts effect a shift in the effective resistive force of the spring on the button, said multiple contacts being spaced different distances from said lever.
 3. A multiple stage push button switch as in claim 1, wherein said means includes a lever acted on by said spring and wherein said means includes abutment means spaced about the axis of said button and located different distances from said lever for engagement by said lever as to shift the direction of action of said lever.
 4. A multiple stage push button switch as in claim 1, wherein said means includes a lever acted on by said spring and wherein the spring is coaxial with the push button, and the lever is a circular member supported in part by a first support element carried by the push button axis, and in part by second support element located a distance from the spring axis which is greater than the distance between the closest portion of said first support element and said axis.
 5. A multiple stage push button switch as in claim 4, wherein the spring is a coil spring, said push button having a stem surrounded by the spring, the circular member being a washer surrounding the stem, a housing in which said push button is mounted, said second support element being one of plural contacts, which contacts are disposed in fixed relation in said housing on the side of said washer opposite said spring, another of said contacts being disposed adjacent the remote side of said stem from said second support and being located to be engaged by said washer as it is depressed to cause said washer to tilt toward still another contact, said contacts being disposed in spaced relation about the axis of said button.
 6. A multiple stage push button switch as in claim 5, wherein said stem projects through said housing, said first support element comprising a clip having a portion passing through said stem to support said washer and confine said spring, and having another portion passing through an opening in said housing and having a latching fit with the projecting portion of said stem, sAid clip having portions engaging said housing in abutting relationship in both directions of movement of said button to limit the movement of said button relative to said housing and retain said button, spring, washer and housing in assembled condition.
 7. A multiple-stage push button switch as in claim 1, wherein said push button is mounted on a housing for movement relative thereto, said means including a lever means establishing stepped operative connections between said spring and said housing to provide abrupt increases in resistance to push button movement as the latter is depressed.
 8. A multiple stage plunger switch comprising: plural spaced contacts, a tilt contact member, a plunger, and means operatively connecting the plunger and the tilt contact member to cause the latter to tilt about a first axis to engage at least one contact and subsequently tilt about another axis, angularly related to the first axis, to engage at least one other contact, said means including a single spring, said spring applying a biasing pressure to said contact member. 